SQLite 的一点点。。。不知道对不对

老毕让我们演示内存数据库来着，找了个，SQLite。官方网站上，下到了源码，和安装文件（其实免安装，几百k）。既然是内存数据，那怎么体现出内存数据库的特征？

不涉及输入输出，所有工作都在内存中进行呢

 

下面是一组对比，开始是把SQLite当磁盘数据库用，把sqlite3.h 和.cpp添加到工程，然后下面程序，很简单，插入25万条数据，打开任务管理器，菜单项-》查看-》选择列。加入IO那些列，待会监测输入输出用

 

#include <iostream>
#include "sqlite3.h"
#include <string>
using namespace std;

int main(){
 

 sqlite3 *db;
 
 char *err_msg = 0;
 
 char * sql_statement = "create table c(id ,name)";

 
 
 int recode;
 
 recode = sqlite3_open("D://test.db",&db);
 
 
 if(recode!=SQLITE_OK)
 {
  
  cout<<"Can't Open Database:  "<<sqlite3_errmsg(db)<<endl;
  
  sqlite3_close(db);
  
 }
 else
 {
  
  cout<<"Open OK!"<<endl;
  
  recode = sqlite3_exec(db,sql_statement,0,0,&err_msg);
  
  
  if(recode!=SQLITE_OK)
  {
   cout<<"error : "<<err_msg<<endl;
   
   sqlite3_close(db);
   
  }
  else
  {
   
   cout<<"create OK!/n";
   
//随便插入的数据,25万条
   recode = sqlite3_exec(db,"begin trasaction",0,0,&err_msg);
   for(int i=0;i<50000;i++)
   {
   recode = sqlite3_exec(db,"insert into c values(1,12) ",0,0,&err_msg);
   recode = sqlite3_exec(db,"insert into c values(1,132) ",0,0,&err_msg);
   recode = sqlite3_exec(db,"insert into c values(1,132) ",0,0,&err_msg);
   recode = sqlite3_exec(db,"insert into c values(1,21) ",0,0,&err_msg); 
   recode = sqlite3_exec(db,"insert into c values(1,12) ",0,0,&err_msg);
   }
   recode = sqlite3_exec(db,"commit",0,0,&err_msg);   
   sqlite3_close(db);
   
  }
  
 }

 system("pause");
 return 0;
}

 

运行就可以监视到io不断增加，内存没有增加

 

 

 

想再次运行，到D盘里把test.db删除了

 

 

 

 

 

这是磁盘数据库

 

下面是内存数据库

在内存打开sqlite

 

 

#include <iostream>
#include "sqlite3.h"
#include <string>
using namespace std;

int

main(){
 
 sqlite3 *db;
 
 char *err_msg = 0;
 
 char * sql_statement = "create table c(id ,name)";

 
 
 int recode; 
 
 recode = sqlite3_open(":memory:",&db);
 
 if(recode!=SQLITE_OK)
 {
  
  cout<<"Can`t Open Database:  "<<sqlite3_errmsg(db)<<endl;
  
  sqlite3_close(db);
  
 }
 else
 {
  
  cout<<"Open OK!/n";
  
  recode = sqlite3_exec(db,sql_statement,0,0,&err_msg);
  
  
  if(recode!=SQLITE_OK)
  {
   cout<<"error : "<<err_msg<<endl;
   
   sqlite3_close(db);
   
  }
  else
  {
   
   cout<<"create OK!/n";
 
   recode = sqlite3_exec(db,"begin trasaction",0,0,&err_msg);
   for(int i=0;i<500000;i++)
   {
   recode = sqlite3_exec(db,"insert into c values(1,12) ",0,0,&err_msg);
   recode = sqlite3_exec(db,"insert into c values(1,132) ",0,0,&err_msg);
   recode = sqlite3_exec(db,"insert into c values(1,132) ",0,0,&err_msg);
   recode = sqlite3_exec(db,"insert into c values(1,21) ",0,0,&err_msg); 
   recode = sqlite3_exec(db,"insert into c values(1,12) ",0,0,&err_msg);
   }
   recode = sqlite3_exec(db,"commit",0,0,&err_msg);   
   sqlite3_close(db);
   
  }
  
 }

 return 0;
 
}

这是插入250万条数据。用任务管理器看到，内存在不断增加，没有任何IO

 

 

 

没有任何IO就体现出内存数据库的特征了吧

 

 

不知道对不对。

 

简单的程序体现内存数据特征